KR101641929B1 - Sola Cell of Thin Film and Method for Fabricating the same - Google Patents

Abstract

The present invention relates to a thin film solar cell including a buffer layer for preventing reduction and vaporization of a front electrode, and a method of manufacturing the thin film solar cell. The thin film solar cell includes a plurality of front electrodes formed on a substrate; A first separator for separating the plurality of front electrodes; A buffer layer located on the plurality of front electrodes; A semiconductor layer formed on the substrate including the buffer layer; A transparent conductive layer formed on the semiconductor layer; A contact portion from which the semiconductor layer and the transparent conductive layer are removed; A plurality of rear electrodes electrically connected to the plurality of front electrodes through the contact parts and formed on the transparent conductive layer; And a second separator which separates the plurality of rear electrodes and from which the semiconductor layer and the transparent conductive layer are removed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a thin film solar cell,

The present invention relates to a thin film solar cell including a buffer layer for preventing reduction and vaporization of a front electrode, and a method of manufacturing the same.

With increasing interest in environmental issues and fossil energy depletion, interest in renewable and environmentally friendly solar cells is increasing as an alternative energy source. Solar cells can be divided into solar cells, which generate the steam needed to rotate the turbine using solar heat, and solar cells, which convert the photons into electrical energy using the properties of semiconductors. Particularly, researches have been actively conducted on photovoltaic cells in which electrons of a p-type semiconductor and holes of an n-type semiconductor are converted into electrical energy by absorbing light.

A solar cell using the properties of a semiconductor is the same as a diode having a junction type of a P-type semiconductor and an N-type semiconductor. When light enters a PN junction where a P-type semiconductor and an N-type semiconductor are in contact with each other, electrons and holes are generated inside the semiconductor due to light energy. Generally, when light having a band gap energy or less enters a semiconductor, it weakly interacts with electrons in the semiconductor. When light having a band gap or more enters, electrons in the covalent bond are excited to generate an electron hole pair as a carrier . The carriers formed by the light return to their normal state through the recombination process. The electrons and holes generated by the light energy are transferred to the N-type semiconductor and the P-type semiconductor by the internal electric field, respectively, and are collected at both electrode portions, and can be used as electric power.

Solar cells are classified into board type solar cells and thin film solar cells. A substrate type solar cell is manufactured by using a silicon wafer as a substrate, and a thin film type solar cell is formed by forming a semiconductor layer in a thin film form on a substrate such as glass. The substrate type solar cell is advantageous in somewhat higher efficiency than the thin film type solar cell, and the thin film type solar cell is advantageous in that the manufacturing cost is reduced as compared with the substrate type solar cell.

Although the substrate type solar cell has a somewhat higher efficiency than the thin film type solar cell, there is a limitation in minimizing the thickness in the process, and a manufacturing cost is increased because an expensive semiconductor substrate is used. Thin-film solar cells are more suitable for mass production because they can be manufactured with a thin thickness and can use low-cost materials and thus have a reduced manufacturing cost, although the efficiency is somewhat lower than that of the substrate-type solar cell.

The thin film solar cell is manufactured by forming a front electrode on a substrate such as glass, forming a semiconductor layer on the front electrode, and forming a rear electrode on the semiconductor layer. Hereinafter, referring to the drawings, Will be described in detail.

1A to 1G are process flow diagrams for manufacturing a thin film solar cell of the prior art.

As shown in FIG. 1A, a front electrode material 20a is formed on a substrate 10. The front electrode material 20a may be zinc oxide (ZnO). 1B, a first isolation region (not shown) is defined in the front electrode material 20a and a first region (not shown) is formed in the front electrode material 20a to remove the separation region of the front electrode material 20a using the first laser L1. A laser scribing process is performed. The front electrode 20 is formed by the first laser scribing process so as to be spaced apart with the first separator 25 therebetween.

Referring to FIG. 1C, a semiconductor material 30a and a transparent conductive material 40a are sequentially stacked on a substrate 10 including a front electrode 20. Each of the semiconductor material 30a and the transparent conductive material 40a uses silicon and ITO (indium tin oxide). A contact region (not shown) is defined in the transparent conductive material 40a and a semiconductor material 30a and a transparent conductive material 40a corresponding to the contact region are formed using the second laser L2 A second laser scribing process is performed. The semiconductor layer 30 and the transparent conductive layer 40 are formed by the second laser scribing process so as to be spaced apart with the contact portion 35 interposed therebetween.

As shown in FIG. 1E, a rear electrode material 50a is formed on a transparent conductive layer 40 including a contact hole 35. 1F, a second separation region is defined in the rear electrode material 50a, and a rear electrode material layer 50a corresponding to the second separation region is removed using the third laser L3. Laser scribing process is performed. The rear electrode 50 spaced apart from the second separator 45 by the third laser scribing process is formed.

Referring to FIG. 1G, a third isolation region is defined on the substrate 10, and a semiconductor 30 (FIG. 1B) which is stacked on the outer portion of the substrate 10 and corresponding to the third isolation region The third separator 55 forms a third separator 55 by removing the transparent conductive layer 40, the rear electrode 50 and the front electrode 20. The third separator 55, In the process of modularizing the completed thin film solar cell, the housing is connected to the thin film solar cell, which prevents electric short between the thin film solar cell and the housing.

The above-described prior art thin film solar cell and its manufacturing method have the following problems.

Generally, zinc oxide (ZnO) is grown in a single crystal by a high pressure crystal growth method using a Zn metal seed. The melting point of zinc oxide (ZnO) used in the high-pressure single crystal growth method is a high temperature of 1970 degrees. However, the chemical bonding of zinc oxide (ZnO) is very unstable, which leads to easy reduction and oxidation at lower temperatures, which is due to the low oxygen binding power of zinc oxide (ZnO). Since the melting point and the vaporization point of reduced zinc (Zn) are 419 degrees and 970 degrees, respectively, the temperature at which zinc (Zn) reduced by laser irradiation can be sufficiently dissolved and vaporized in a scribing process using laser Lt; / RTI >

A plurality of front electrodes 20 formed of zinc oxide (ZnO) are reduced by the heat radiated from the third and fourth lasers L3 and L4 when the rear electrode 50 is formed, Oxygen generated in the reduction can be supplied to the semiconductor layer 30 formed of silicon to form silicon oxide. Reduced zinc (Zn) is vaporized by the irradiation of the laser and remains in the second and third separators 45 and 55 to cause electrical short between a plurality of unit cells. Then, silicon oxide is formed in the semiconductor layer 30, which may lower the function of the diode. Since the reduction and oxidation of zinc oxide (ZnO) and silicon are performed at a low temperature, a large number of the front electrode 20 and the semiconductor layer 30 are affected in the third and fourth laser scribing processes, There is a problem that processing of the solar cell becomes difficult.

1G, a fourth laser scribing process is performed to form a third separator 55, and then a plurality of rear electrodes 50 are connected in series to modularize the thin film solar cell . In a thin film solar cell, a plurality of unit cells are isolated from each other, and a plurality of rear electrodes 55 are connected in series in a modulating process. In the case where the front electrode 20 using zinc oxide (ZnO) is formed and the semiconductor layer 30 is formed of silicon, in the third and fourth laser scribing processes, The zinc oxide (ZnO) corresponding to the first and the second separators 45 and 55 is reduced and the reduced zinc oxide (ZnO) is vaporized by the irradiation of the laser and thereafter is again deposited on the second and third separators 45 and 55 Oxygen generated by the reduction of zinc oxide (ZnO) can be supplied to the semiconductor layer 30 to form a silicon oxide, and a short phenomenon in which a plurality of unit cells are electrically connected to each other. As a result, defects may occur in the thin film solar cell module.

In order to solve the problems of the prior art described above, the present invention is characterized in that a buffer layer is formed between the front electrode and the semiconductor layer so that the reduction and oxidation of the front electrode and the semiconductor layer, And preventing electrical connection between adjacent unit cells due to redeposition of the vaporized vapor to the substrate, and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a thin film solar cell comprising: a plurality of front electrodes formed on a substrate; A first separator for separating the plurality of front electrodes; A buffer layer located on the plurality of front electrodes; A semiconductor layer formed on the buffer layer; A transparent conductive layer formed on the semiconductor layer; A contact portion from which the semiconductor layer and the transparent conductive layer are removed; A plurality of rear electrodes electrically connected to the plurality of front electrodes through the contact parts and formed on the transparent conductive layer; And a second separator which separates the plurality of rear electrodes and from which the semiconductor layer and the transparent conductive layer are removed.

In the thin-film solar cell, the plurality of front electrodes are formed of zinc oxide (ZnO).

The thin-film solar cell may further include a third separator in which the semiconductor layer and the transparent conductive layer corresponding to the outer edge of the substrate are removed.

In the thin-film solar cell, the buffer layer may be an insulating material or a conductive material.

In the thin-film solar cell, the buffer layer may be selected from Al ₂ O ₃ , SiO ₂ , Si ₃ N ₄ , NiO, and TiO ₃ .

In the above thin-film solar cell, the buffer layer is formed to a thickness of 1 to 3 nm.

In the thin-film solar cell, when the buffer layer is used as a bi-stable resistance, the buffer layer is formed to a thickness of 1 to 10 nm.

In the thin-film solar cell, the plurality of rear electrodes are connected in series.

According to another aspect of the present invention, there is provided a method of manufacturing a thin film solar cell, including: forming a front electrode material layer on a substrate; Forming a buffer layer on the front electrode material layer; Defining a first isolation region in the buffer layer, removing the front electrode material layer and the buffer layer corresponding to the first isolation region to form a first isolation region; Sequentially forming a semiconductor layer and a transparent conductive layer on the substrate including the buffer layer; Defining a contact region on the transparent conductive layer, removing the semiconductor layer and the transparent conductive layer corresponding to the contact region to form a contact portion; Forming a rear electrode material layer on the transparent conductive layer including the contact portion; And defining a second isolation region in the rear electrode material layer and removing the rear electrode material layer, the transparent conductive layer, and the semiconductor layer corresponding to the second isolation region using a laser irradiation method, And forming a plurality of rear electrodes separated by the second separator and electrically connected to the plurality of front electrodes through the respective contact portions.

In the method of manufacturing a thin film solar cell as described above, a third isolation region may be defined in an outer portion of the substrate, and the rear electrode material layer, the transparent conductive layer, And forming the third separator by removing the semiconductor layer.

In the method of manufacturing a thin film solar cell as described above, the plurality of front electrodes are formed of zinc oxide (ZnO).

In the method of manufacturing a thin film solar cell as described above, the buffer layer may be an insulating material or a conductive material.

In the manufacturing method of the thin-film solar cell, the buffer layer may be selected from Al ₂ O ₃ , SiO ₂ , Si ₃ N ₄ , NiO, and TiO ₃ .

In the method of manufacturing a thin film solar cell as described above, the buffer layer is formed to a thickness of 1 to 3 nm.

When the buffer layer is used as a bi-stable resistance, the buffer layer is formed to a thickness of 1 to 10 nm.

The thin film solar cell of the present invention and its manufacturing method have the following effects.

In the solar cell, the front electrode can be formed of a material which is unstable in chemical bonding such as zinc oxide (ZnO) and is easily reduced or vaporized for various reasons including reduction of manufacturing cost. The present invention relates to a method of removing a semiconductor layer, a transparent conductive layer and a rear electrode stacked on a front electrode by forming a buffer layer of an insulating material or a conductive material chemically stable and having a high bandgap on the front electrode formed of zinc oxide (ZnO) The front electrode is reduced and vaporized in the laser scribing step of forming the separation part, and the vaporization is again deposited on the separation part, thereby preventing the failure of electrically connecting adjacent unit cells.

In addition, in the laser scribing process in which the semiconductor layer, the transparent conductive layer, and the rear electrode stacked on the front electrode are removed to form a separation portion by forming a buffer layer between the front electrode and the semiconductor layer, ZnO) is supplied to the semiconductor layer to prevent oxidation of the semiconductor layer.

Figs. 1A to 1G are flow charts for manufacturing a thin film solar cell of the prior art
FIGS. 2A to 2G are flow charts for manufacturing a thin film solar cell according to an embodiment of the present invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A to 2G are process flow diagrams for manufacturing a thin film solar cell according to an embodiment of the present invention.

Referring to FIG. 2A, a front electrode material 200a is formed on a substrate 100. FIG. As the substrate 100, one of glass, transparent plastic, and flexible plastic can be used. The front electrode material 200a is formed by a metal organic chemical vapor deposition (MOCVD) process, a plasma enhanced chemical vapor deposition (PECVD) process, a sputtering process, an e-beam process, .

The front electrode material 200a is formed of Ag, Al, Ag + Al, Ag + Mg, Ag + Mn, Ag + Sb, Ag + Zn, Ag + Mo, Ag + Ni, Ag + Cu, Or a metal such as ITO (indium tin oxide), FTO (fluorine doped tin oxide), ZnO, ZnO: B, ZnO: Al, Ag, SnO ₂ , SnO ₂ : F, ZnO: Ga ₂ O ₃ , ZnO: Al ₂ O ₃ , SnO ₂ : Sb ₂ O _3, and the like. In the present invention, zinc oxide (ZnO) may be used as the front electrode material 200a in order to reduce the manufacturing cost of the solar cell.

Since the front electrode material 200a is a surface on which sunlight is incident, it is important that the incident sunlight can be absorbed into the solar cell as much as possible. To this end, a texturing process is applied to the front electrode layer 200a Can be performed. The roughening process is a process of forming the surface of the front electrode material 200a in a concave-convex structure, and may be performed by selecting one of a photolithography process, a mechanical process, and a groove forming process using physical processing. have. Photolithography can also be divided into anisotropic and isotropic etching processes using dry and wet etching. When the surface roughening process is performed on the front electrode material 200a, the ratio of the incident sunlight to the outside of the solar cell is reduced, and the sunlight is scattered into the solar cell due to the scattering of incident sunlight. So that the efficiency of the solar cell is improved.

In the roughening process, the roughening process may be used to form the roughened structure on the surface of the substrate 100. The surface of the front electrode material 200a has the same concavo-convex structure as the concavo-convex structure formed on the surface of the substrate 100 due to the concavo-convex structure formed on the surface of the substrate 100. [

A buffer layer 250 is formed on the front electrode 200a after the roughening process is completed. The buffer layer 260 may be formed by a metal organic chemical vapor deposition (MOCVD) process, a plasma enhanced chemical vapor deposition (PECVD) process, a sputtering process, an e-beam process, have. The buffer layer 260 is interposed between the front electrode 200 and the semiconductor layer 300 to be described later. The front electrode 200 is formed of zinc oxide (ZnO) by the laser generated in the scribing process using the laser, And the vaporization of the semiconductor layer 300 formed of silicon.

The buffer layer 260 may be made of a material that is chemically stable and has a relatively high band gap and may prevent reduction and vaporization of zinc oxide (ZnO). If the material is a material, the insulating material or the conductive material may be used without limitation . The buffer layer 260 may use one or a mixture of two or more of Al ₂ O ₃ , SiO ₂ , Si ₃ N ₄ , NiO and TiO ₃ . When an insulating material is used for the buffer layer 260, the buffer layer 265 may be formed to a thickness of 1 to 3 nm, which has a large tunneling effect and a low bleach down voltage. When nickel oxide (NiO), which is a bi-stable resistance material, is used, the buffer layer 260 may be formed to a thickness of 1 to 10 nm.

2B, a first isolation region (not shown) is defined in the buffer layer 260 and a first laser L1 (not shown) is formed on the buffer layer 260 and the front electrode material 200a through the substrate 100, The buffer layer 260 and the front electrode material 200a corresponding to the first isolation region are removed by irradiating the buffer layer 260 and the front electrode material 200a directly with the first laser L1 A first laser scribing process is performed to form a plurality of front electrodes 200 spaced apart with the first separator 250 therebetween. The first laser L1 may use an infrared (IR) laser.

2A and 2B, after the front electrode material 200a and the buffer layer 260 are formed on the entire surface of the substrate 100, the buffer layer 260 and the front electrode material 200a corresponding to the first isolation region are formed. (Inkjet Printing) method, gravure printing method, or fine contact printing method (for example, a screen printing method, an inkjet printing method, or a gravure printing method) may be used instead of the method of forming a plurality of front electrodes 200, It is also possible to form a plurality of front electrodes 200 spaced apart with the first separator 250 therebetween on the substrate 100 by a method such as micro contact printing.

The screen printing method uses a screen and a squeeze to transfer the target material to the workpiece

The inkjet printing method is a method of forming a pattern by spraying an object material onto an object using an inkjet. Gravure printing method is a method of applying a substance to a groove of a concave plate, A method of forming a pattern by transferring to a workpiece, and a fine contact printing method is a method of forming a pattern of an object material on a work using a mold. When the front electrode 200 is formed by using the screen printing method, the inkjet printing method, the gravure printing method, or the fine contact printing method, the possibility that the substrate is contaminated is reduced compared with the case of using the laser scribing process, The cleaning process for preventing the contamination of the wafer is also reduced.

Next, as shown in FIG. 2C, a semiconductor material 300a and a transparent conductive material 400a are sequentially formed on the substrate 100 including the front electrode 200 and the buffer film 250. Next, as shown in FIG. The semiconductor material 300a may be formed using a CVD process or the like. The semiconductor material 300a may be formed of a PIN structure in which a P-type semiconductor material, an I-type semiconductor material, and an N-type semiconductor material are sequentially stacked.

When the semiconductor material 300a is formed into a PIN structure, the I-type semiconductor material is depleted by the P-type semiconductor material and the N-type semiconductor material, and an electric field is generated therein. Holes and electrons are drifted by the electric field to be collected from the P-type semiconductor material and the N-type semiconductor material, respectively. Meanwhile, when the semiconductor material 300a is formed into a PIN structure, it is preferable to form a P-type semiconductor material on the front electrode 200 and then form an I-type semiconductor material and an N-type semiconductor material. The reason for this is that the drift mobility of holes is generally low due to the drift mobility of electrons, so that the P-type semiconductor material is formed close to the light receiving surface in order to maximize the collection efficiency by the incident light.

The transparent conductive material 400a may be formed using a transparent conductive material such as ZnO, ZnO: B, ZnO: Al, or Ag by a sputtering method or an MOCVD (Metal Organic Chemical Vapor Deposition) method. The transparent conductive material 400a scatters sunlight and proceeds at various angles, thereby increasing the ratio of light reflected from the rear electrode to be incident on the semiconductor material 300a.

A contact region (not shown) is defined in the transparent conductive material 400a and the second laser (not shown) is formed on the semiconductor material 300a and the transparent conductive material 400a through the substrate 100, L2 to remove the semiconductor material 300a and the transparent conductive material 400a corresponding to the contact region by irradiating the semiconductor laser 300a and the transparent conductive material 400a directly with the second laser L2, Laser scribing process is performed. The contact portion 350 is formed through the second scribing process. A plurality of semiconductor layers 300 and a transparent conductive layer 400 which are spaced apart from each other by a contact portion 350 are formed by the second scribing process. Here, a green laser may be used as the second laser L2. In order to minimize the dead zone of the solar cell, the contact portion 350 may be formed adjacent to the first separator 250.

Each of the semiconductor layers 300 should be electrically connected to the plurality of front electrodes 200. Therefore, when the buffer layer 260 interposed between the semiconductor layer 300 and the front electrode 200 is formed of an insulating material, an insulating material having a high tunneling effect and a low breakdown voltage is formed into a thin film, 200 and the semiconductor layer 300 are electrically connected to each other.

Referring to FIG. 2E, a rear electrode material 500a is formed on the transparent conductive material 400a including the contact part 350. Referring to FIG. The rear electrode material 500a may be formed by an MOCVD process, a PECVD process, or a sputtering process. The back electrode material 500a may be formed of Ag, Al, Ag + Al, Ag + Mg, Ag + Mn, Ag + Sb, Ag + Zn, Ag + Mo, Ag + Ni, Ag + Cu, formed using the same metal material or, ITO, FTO, ZnO, ZnO : B, ZnO: Al, Ag, SnO 2, SnO 2: F, ZnO: Ga 2 O 3, ZnO: Al 2 O 3, SnO 2: Sb ₂ O _3, and the like.

A second isolation region (not shown) is defined on the rear electrode material 500a and the rear electrode material 500a, the transparent conductive layer 400, and the semiconductor layer 300 A third laser scribing process is performed to form the second separator 450 by removing the first thin film corresponding to the second isolation region by irradiating the third thin film with the third laser L3. A plurality of rear electrodes 500 spaced apart from each other with the second separator 450 therebetween are formed and connected in series through the rear electrode 500 formed on the contact unit 350 and the second separator 450 A plurality of unit cells are formed in the solar cell separated by the plurality of unit cells. Here, the third laser L3 may be a green laser having a wavelength of about 532 nm ± 5 nm and a frequency of about 7 kHz.

A buffer layer 260 is interposed between the front electrode 200 and the semiconductor layer 300. Therefore, the buffering layer 260 can prevent the reduction of the front electrode 200, which is formed of zinc oxide (ZnO) and corresponds to the second separator 450. The oxidation of the semiconductor layer 300 can be prevented and the zinc (Zn) reduced by the heat of the third laser L3 is vaporized And is not deposited on the second separator 450. As described above, the buffer layer 260 functions to prevent zinc oxide (ZnO) from being reduced at a low temperature due to chemical instability.

In the third laser scribing process, the rear electrode material 500a, the transparent conductive layer 400, and the semiconductor layer 300 corresponding to the second separator 450 are removed to form the second separator 450 , The process proceeds so that the buffer layer 260 is not removed. However, even if a portion of the buffer layer 260 is removed, the third laser scribing process is completed at the time when the buffer layer 260 is removed, so that the reduction and vaporization of the front electrode 200 can be prevented. Therefore, it is possible to prevent the front electrode 200 made of zinc oxide (ZnO) from vaporizing and being deposited again on the second separator 450 to short-circuit the adjacent solar cell. In addition, oxidation of the semiconductor layer 300 can be prevented.

Since the transparent conductive layer 400 and the semiconductor layer 300 are removed after the rear electrode material 500a is removed in the process of forming the second separator 450, The contact failure between the rear electrode 500 and the front electrode 200 does not occur. In addition, the dead zone of the solar cell can be minimized by arranging the second separator 450 adjacent to the contact part 350. [ The rear electrode material 500a may be formed by a screen printing method, an inkjet printing method, a gravure printing method, or a fine contact printing method.

2G, a third isolation region (not shown) is defined in the outer portion of the substrate 100 and the rear electrode material 500a, the transparent conductive layer 400, the semiconductor layer 300, The second thin film including the electrode 200 is irradiated with the fourth laser L4 to remove the second thin film corresponding to the third separation region to form the third separation unit 550. [ Here, the fourth laser L4 may be an infrared (IR) laser having a wavelength of about 1060 ± 10 nm and a frequency of about 40 kHz. The third separator 550 connects the housing to the thin-film solar cell in the process of modularizing the completed thin-film solar cell, thereby preventing electrical short between the housing and the thin-film solar cell.

A buffer layer 260 is interposed between the front electrode 200 and the semiconductor layer 300. Therefore, the buffer layer 260 prevents the reduction of the front electrode 200, which corresponds to the third isolation portion 550 and is formed of zinc oxide (ZnO). The reduction of zinc oxide (ZnO) is prevented and the supply of oxygen is interrupted, so that the oxidation of the semiconductor layer 300 can be prevented, and the zinc (Zn) reduced by the heat of the fourth laser L4 is vaporized And is not deposited on the third separator 550. As described above, the buffer layer 260 functions to prevent zinc oxide (ZnO) from being reduced at a low temperature due to chemical instability.

In the fourth laser scribing process, the rear electrode material 500a, the transparent conductive layer 400, and the semiconductor layer 300 corresponding to the third separation unit 550 are removed to form the third separation unit 550 , The process proceeds so that the buffer layer 260 is not removed. However, even if a portion of the buffer layer 260 is removed, the fourth laser scribing process is completed at the time when the buffer layer 260 is removed, so that the reduction and vaporization of the front electrode 200 can be prevented. Therefore, it is possible to prevent the front electrode 200 made of zinc oxide (ZnO) from vaporizing and being deposited again on the second separator 450 to short-circuit the adjacent solar cell.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. It is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. .

Claims (15)

A plurality of front electrodes formed on the substrate;
A first separator for separating the plurality of front electrodes;
A buffer layer located on the plurality of front electrodes;
A semiconductor layer formed on the buffer layer;
A transparent conductive layer formed on the semiconductor layer;
A contact portion from which the semiconductor layer and the transparent conductive layer are removed;
A plurality of rear electrodes electrically connected to the plurality of front electrodes through the contact parts and formed on the transparent conductive layer; And
And a second separator which separates the plurality of rear electrodes and from which the semiconductor layer and the transparent conductive layer are removed,
The buffer layer,
And a barrier rib interposed between the contact portion and the front electrode to cut off communication between the contact portion and the front electrode,
A second separator interposed between the second separator and the front electrode to block communication between the second separator and the front electrode,
Wherein when the buffer layer is used as an insulating material, the buffer layer is formed to a thickness of 1 nm to 3 nm.
The method according to claim 1,
Wherein the plurality of front electrodes are formed of zinc oxide (ZnO).
The method according to claim 1,
Further comprising a third separator, in which the semiconductor layer and the transparent conductive layer corresponding to the outer frame of the substrate are removed.
delete The method according to claim 1,
Wherein the buffer layer is selected from Al ₂ O ₃ , SiO ₂ , Si ₃ N ₄ , NiO, and TiO ₃ .
delete delete The method according to claim 1,
And the plurality of rear electrodes are connected in series.
Forming a front electrode material layer on the substrate;
Forming a buffer layer on the front electrode material layer;
Defining a first isolation region in the buffer layer, removing the front electrode material layer and the buffer layer corresponding to the first isolation region to form a first isolation region;
Sequentially forming a semiconductor layer and a transparent conductive layer on the substrate including the buffer layer;
Defining a contact region on the transparent conductive layer, removing the semiconductor layer and the transparent conductive layer corresponding to the contact region to form a contact portion;
Forming a rear electrode material layer on the transparent conductive layer including the contact portion; And
By defining a second isolation region in the rear electrode material layer and removing the rear electrode material layer, the transparent conductive layer, and the semiconductor layer corresponding to the second isolation region using a laser irradiation method, And forming a plurality of rear electrodes separated by the second separator and electrically connected to the plurality of front electrodes through the respective contact portions,
The buffer layer,
And a barrier rib interposed between the contact portion and the front electrode to cut off communication between the contact portion and the front electrode,
A second separator interposed between the second separator and the front electrode to block communication between the second separator and the front electrode,
Wherein when the buffer layer is used as an insulating material, the buffer layer is formed to a thickness of 1 nm to 3 nm.
10. The method of claim 9,
A third separation region is defined in an outer portion of the substrate, and the rear electrode material layer, the transparent conductive layer, and the semiconductor layer corresponding to the third separation region are removed using a laser irradiation method, And forming the thin film solar cell.
10. The method of claim 9,
Wherein the plurality of front electrodes are formed of zinc oxide (ZnO).
delete 10. The method of claim 9,
Wherein the buffer layer is selected from Al ₂ O ₃ , SiO ₂ , Si ₃ N ₄ , NiO, and TiO ₃ .
delete delete

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